Spark plug and method of making the same



1941- H. J. FANGER SPARK PLUG AND METHOD OF MAKING THE SAME Filed May 24, 1940 8 EMISSIVE IONIZATION MATERIAL INVENTOR, HERMAN J. FANGER.

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c I 2,261,436 UNITED. STATES PATENT! 1 OFFICE Patented Nov)" 4, 1941 p 2.261.436 I srzmx PLUG AND im'rnon or MAKING 'rns sum Herman J. Fanger, Oakland, CaliL, assignor oi (bra-half to Edmund 11.. Week, In, Oakland,

Application May 24, 1940, Serial No. 336,974

12 Claims. (C1. 123-169) The present invention relates to improvements Figure 1 shows a side elevation of a spark plug in spark plugs and a method of making the having my improvements incorporated therein; same, and its principal object is to provide a Figure 2,.an enlarged sectional view of the spark plug for an internal combustion engine lower part of the spark plug; that will produce a hotter spark, reduce the volt- 5. Figure 3, a horizontal section through the elecage required to jump a given gap and thus pertrode, on an enlarged scale, taken along line mit the flow of a greater amperage across it, 3-3 of Figure 2; thereby insuring a more thorough combustion Figur 4. a horizontal e ion hrou h a modior the gas, and, as a result, an increase in power fled form of electrode; and and flexibility in the internal combustion engine. .10 Figu a similar section through a further More particularly it is proposed to provide d fied fo m of my invention. certain improvements in one or both of the elec- Wh I have s ow o y t e preferred forms trodes of the spark plug whereby a stratum of of my inv n n. I Wish to have it understood emissive material is incorporated in the tip of that Various changes ifi a n m y be the electrode for ionizing the gap between the m e Wi hin the scope of the claims hereto ate1 ct d tached, without departing from the spirit of the It is further proposed to arrange the emissive i11Veht1oh--M1e Particularly. it s ould be undermaterial in one or more layers extending lengthstood t while I have described y i v tion wise into the body of the electrode to a con- P n y in connection with a spark P l csiderable depth 50 that when the extreme ext certain principles thereof y be d y posed portiorrof such material wears away, 9. applied to electrodes gen ally. pocket or groove is left which still exposes the Figure 1 ill r s aconventional'type of spark plug I having the two electrodes 2 and 3 ar- It is further proposed to join the emissive ranged to form a p p 4 be ween the same. material to the other material of the electrode The Present invention resides Pr c pal y in the by e hanical a a by r r whereby particular construction shown in connection with the materials are forced into intimate contact theelectl'ode The same construction, without impairing the emissive properties of the ever, could he pp d to the other electrode emissive material, Or to both electrodes, if desired.

A further object of my invention is to pro The electrode 3 s shown i Fi res 2 and 3 vide an electrode for a spark plug or the like as comprising col'e which is Preferably e in which the portion of the electrode exposed of nickel or p ul r member 6 surto the heat of the combustion chamber, hereinr ding the core so as to leave an annular after described as the tip of the electrode, is spacing, as at and an u ar layer 8 intermade particularly with a view of resisting heat 5 Posed between the e a t e tubular member. and corrosion, whereas the portion thereof Thelntel'posed l y r consists of emissive mamounted remote from the combustion chamber tel-i911 adapted to cause ionization of the p is made of material having particularly ttween the two electrodes whereby the properties conducting properties. of the spark are much p oved. The emissive Another important object of the present in- 40 material itself is well-known in the art and may vention, in its preferred form, is to make the comprise a large Variety of different mixtures, tip of the electrode itself of different metals, c as, for instance, ny one of a group nan outer layer being selected with a view of reeluding barium oxide, strontium o d c rium sisting heat and corrosion, and the inner portion dioxide and thorium oxide, mixed with carbon with a view of conducting heat away from the and a suitable in r, such as molasses.- combustion chamber, and also with a view, in It will b noted that the ve aterial is one preferred form atleast, of-yielding to wear exPOsed the gap and folms a annular ring somewhat more rapidly than the outer mateacing the same. In use the ring Wil we aw y rial, whereby a cupped efiect is produced which to a certain ep h so as to form an annular facilitates the spark discharge. groove w ich still exposes the emissive material.

And finally I propose in the present invention As the latter wears away, the adjacent edges of to provide a number of different methods by the core and of the tubular member will also which the said material may be incorporated in wear to a certain extent so as to round into the the electrode in the desired manner. groove.

Further objects and advantages of my i If the core is made of copper, the entire thicktion will appear as the specification proceeds and s w W w o a certain p h, h r by the novel features thereof will be fully set forth producing a cup eflect w h is favorable to m the claims hereto appended. and facilitates the spark discharge. If the core The preferred forms of my invention are 11- is made of nickel, this would be true to a less exlustrated in the accompanying drawing, forming tent, but a natural rounding off at the edges part of this application, in which: 7 would still occur, leaving a scalloped cross-section, with the emissive material exposed inthe bottom of the groove.

The entire electrode may.be made of the same construction throughout the length thereof, but it is also possible to use a main upper section I of electrode of different construction and a tip section I ll made in accordance with my invention, the tip section being capable of being welded to 4 the main body section, as at H.

' If the electrode is made in two pieces, I preferably use copper for the upper portion of the electrode which is protected by the body of the plug, because copper is a good conductor of heat and tends to carry heat away from the combustion chamber. The lower part or tip section of the electrode should be made in accordance with my invention, as above described, preferably with a heat and corrosion resisting outer layer, such as nickel, and a core made either of copper to encourage heat conduction or of nickel or similar material to resist corrosion, whichever property seems most desirable under given conditions.

It is also possible, of course, to use a tip of conventional construction, without emissive material, but heat and corrosive resistant, and to attach the same to a body made of material selected principally for its heat conducting prop- -'erties, such as copper.

Since the electrode of a spark plug is of a rather small diameter, usually not more than one tenth of an inch, the construction of my electrode offers certain diillculties, which I have successfully overcome in a number of different ways.

In disclosing these methods, I do not wish to be understood as confining myself to the particular methods of making the electrode, but desire protection on the electrode itself, regardless of the methods by which it is made.

To produce the electrode shown in Figure 3, I first make the same of much larger dimensions. I might, for instance, use a core of about threesixteenths of an inch in diameter, apply a pasty coat of the emissive material to the surface, making the layer about one sixty-fourth of an inch thick, baking the layer and then introducing the core with the layer into a tubular member which may be about three-sixteenths of an inch thick. This would make the total diameter somewhat over one-half of an inch.

This assembly, thus constructed, is then attenuated by a swaging process to the thinness desired, which is about one-tenth of an inch in diameter. It is then cut into proper lengths to form complete electrodes, or mere tips forelectrodes.

Another method, for producing a suitable electrode of the type shown in Figure 4, may be described as follows:

A thin plate ii of copper or nickel may be coated with a film of emissive material and may then be rolled spirally into the form illustrated in Figure 4. It is then approximately tubular and may be pushed into a retaining tube I6,

which is preferably made of nickel. After completion, it may be attenuated in the manner previously described.

A third method ofconstruction is illustrated in Figure 5, according to which a number of wire strands H are coated with the emissive material, and are bundled into approximately cylinderical form and pushed into the retaining tube l8. Any voids which may exist between the strands will be squeezed out in the attenuating process.

In the forms shown in Figures 4 and 5, theselectlon of materials is subject to the same .considerations as in the form shown in Figure 3. The outer material should be particularly resistent to heat and corrosion, while the material used on the inside may be either the same or may be selected more with a view of encouraging heat conduction.

I claim:

1. A spark plug having an electrode containing albody of emissive material facing the gap of the D 118. i

2. A spark plug having an electrode containing a body of emissive material mechanically confined therein so as to face the gap of the plug.

3. A spark plug having an electrode containing a body of emissive material mechanically held therein so as to face the gap of the plug, the body of emissive material extending into the electrode to a substantial depth.

4. A spark plug having an electrode containing a body of emissive material mechanically held therein so as to face the gap of the plug, the body of emissive material extending into the electrode to a substantial depth and being of sub stantially uniform cross-section.

5. A spark plug having an electrode comprising a rod of heat-conducting material having a tip secured thereto, the tip having emissive material embedded therein so as to be exposed at the free end of the tip, and the emissive material extending uniformly throughout the length of the tip.

6. The method of making an emissive electrode which comprises coating a rod with emissive material and surrounding the coated rod with a retaining wall.

7. The method of making an emissive electrode which comprises coating a rod with emissive material, surrounding the coated rod with a retaining wall and attenuating the resulting assembly to a desired thinness.

8. The method of making an emissive electrode which comprises coating a sheet of material with emissive material, spirally rolling the sheet into tuabilular form and surrounding it with a retaining w 9. The method of making an emissive electrode which comprises coating a plurality of rods with emissive material, bundling the rods to form a tubular assembly and surrounding the assembly with a retaining wall.

10. An electrode for a spark plug or the like having a free end comprising an outer retaining wall of heat and corrosive resisting material, a core facing the gap of the spark plug and being of less resisting material, and a body of emissive material confined with the core within the retaining wall and extending into the electrode to a considerable depth, whereby upon use portions of the core and the emissive material wear away to form a cup in the bottom of which the core and the emissive material are exposed.

11. An electrode for a spark plug or the like having a tip comprising an outer wall of heat and corrosion resistant material and a core of material having a high degree of heat conductivity and having a body of emissive material mechanically held within the outer wall so as to face the gap of the spark plug.

12. An electrode for a spark plug or the like having a tip with a body of emissive material mechanically held therein so as to face the gap of the spark plug.

' HERMAN J. FANGER. 

